Question

A decrease in plasma volume will decrease plasma hydrostsatic pressure. This can be detected by the cardiovascular baroreceptors which send a signal to the cardiovascular control center which sends nervous impulses to the arterioles to constrict. Constriction decreases flow to the capillary beds, in turn decreasing flow out of the capillaries at the capillary beds served by this arteriole. This prevents further decrease in plasma volume.

• Is this an osmotic mechanism?
• Is this a homeostatic mechanism?
• Is it negative feedback? Positive feedback?
• Define each of these terms and explain your answer to each of these questions.

Answer 1

This is a clear case of homeostatis amd negative feedback mechanism.Here body tries to restore the normal environment which is called as homeostatic mechanism .it is restored by negative feedback, that is by decreasing the plasma volume further.

Explanations are:

OSMOSIS

osmosis is the spontaneous net movement of solvent molecules through a selectively permeable membrane to a region of higher solute concentration inorder to equalize the concentration in both sides.

HOMEOSTATIC MECHANISM

Homeostatis is the regulation of internal conditions of a cell

Or organism to maintain optimum conditions for function in response to internal or external changes.

NEGATIVE FEEDBACK

It is a feedback that cause decrease in fuction as a response to any stimulus. With negative feedback the output reduces the original effect of stimulus.thermoregulation is an example for negative feedback.

POSITIVE FEEDBACK

This increases or amplifies the fuction.here the output increases the original effect of stimulus. For example, during labor oxytoxin is released to increase contractions.